1. Field of the Invention
The present invention relates to a platen device of an ink-jet printer, which is arranged to hold a work fabric or other workpiece, such as a T-shirt, during a printing operation on the workpiece.
2. Discussion of Related Art
A silk-screen printer is conventionally used to print a desired image on a work fabric before the printed work fabric is cut and stitched into a desired garment. For instance, the printed fabric is cut and stitched into a T-shirt such that the printed image is located in the front (bosom) or the back of the T-shirt. The printing method using the silk-screen printer is suitable for a relatively large lot production of a relatively small number of kinds of garments in factories, but is not suitable for a relatively small lot production of a relatively large number of kinds of garments which have different unique patterns of printed image desired or selected by the users or consumers.
In view of the above-indicated drawback of the silk-screen printing on work fabrics, various methods of printing desired patterns of image on unprinted garments or cloths have been proposed for producing a relatively wide variety of printed garments in a relatively small lot size. For personal and household printing of unprinted garments, it has been a common practice, for example, to first prepare an intermediate printing medium having an image, and then transfer the image from the medium onto an unprinted garment such that the medium and the unprinted garment are superposed on each other and subjected to a heat and/or pressure for facilitating the transfer of the image from the medium onto the unprinted garment and fixing the image on the garment. The intermediate printing medium is typically a decalcomania paper carrying an image formed by copying or printing with a transferable material, or a special paper carrying an image formed by copying or printing with a transferable toner or ink.
For industrial production of a relatively large number of kinds of printed garments from unprinted garments or cloths in a relatively small lot size, it has been proposed to use a specially designed printer which is connected to a personal computer and operable to print desired patterns of image on unprinted T-shirts or other unprinted garments according to image data stored in a memory of the personal computer. JP-A-5-84887 discloses an example of this type of printer, which has a table provided with an ink jetting device which is fixed on the table and operable to deliver an ink directly on the surface of an unprinted garment held on the table. The ink jetting device includes a printing head which is movable in two mutually perpendicular directions on the unprinted garment, to print the image with the delivered ink.
JP-A-11-227171 discloses an example of a printing device which has an upper belt and a lower belt which cooperate to hold and feed an unprinted garment such as a T-shirt, and a printing head which is movable in a direction perpendicular to the feeding direction of the unprinted garment and operable to deliver an ink on the unprinted garment.
In the printer disclosed in the above-identified publication JP-A-5-84887, the table is provided with a frame arranged to hold the T-shirt or other unprinted garment on the table such that the front and back of the T-shirt, for example, are superposed on each other, that is, two layers of the T-shirt fabric are held in direct contact with each other. In this state, the upper fabric layer (e.g., the front or bosom of the T-shirt) is relatively likely to float away from the lower fabric layer (e.g., the back of the T-shirt) and have some crease. The publication proposes a solution to this problem, namely, proposes to provide a plurality of sensors for detecting distances between the upper surface of the unprinted garment and respective ink heads of the ink jetting device which correspond to respective different colors. The vertical positions of the ink heads are automatically adjusted according to the detected distances, so that the distances of the ink heads to the upper surface of the garment are held constant. However, this arrangement suffers from another problem of increased complexity in the construction and control of the printer.
Where an ink is delivered on the mutually superposed two layers of fabric of the unprinted garment such as the T-shirt, the ink may undesirably permeate through the upper fabric layer into the lower fabric layer, if the fabric has a relatively small thickness or a relatively coarse texture, or if the ink has a relatively low viscosity. The printer using the frame has a further problem that the unprinted garment must be carefully set on the frame such that non-printing portions of the garment such as the sleeves and hem or lower portions are neatly placed on the upper surface of the table, so as to prevent an interference of those non-printing portions with movable components such as the ink heads, that is, so as to prevent the non-printing portions of the garment from being an obstacle to the movable components. The printer in question has another problem due to similar or equal tensioning of the garment held by the frame in all directions irrespective of the direction of weaving of the fabric. Namely, if the fabric of the garment is printed while the fabric held by the frame is elongated in the direction in which the fabric is relatively easily elongated, the image printed on the fabric may deform due to shrinkage of the fabric to the original state after the fabric is removed from the frame.
In the printing device disclosed in the above-identified publication JP-A-11-227171, the ink is delivered onto the garment such as the T-shirt through an opening formed in the upper belt during feeding of the garment while the garment is held in a generally horizontally extending attitude by and between the upper and lower belts, with the upper and lower fabric layers being superposed on each other. Accordingly, like the printer using the frame, the printer using the upper and lower belts may also suffer from undesirable permeation of the ink through the upper fabric layer into the lower fabric layer. Further, this printer tends to be large-sized.